Johnson Controls Frick 1179, Руководство пользователя, Страница: 22 / 64

RWH ROTARY SCREW COMPRESSOR UNITS
OPERATION
070.620-IOM (DEC 12)
Page 22
INITIAL START-UP PROCEDURE
Having performed the checkpoints on the prestart check
list (see FORMS section), the compressor unit is ready for
start­up. It is impor tant that an adequate refrigerant load
be available to load test the unit at normal operating condi­
tions. The following points should be kept in mind during
initial start­up.
1. It is imperative that during the initial start-up of the
package that the hand expansion valve on the main oil
injection line is open to ensure adequate oil flow. Refer to
the project documents for recommended opening. There is
still an orifice installed in the compressor to control maximum
oil flow. At initial start­up of the package the hand expansion
valve must be fully open. After initial start­up of the package
the hand expansion valve should be adjusted. There are two
methods of determining the correct adjustment of this valve.
The best method to determine target discharge temperature
is to run CoolWare™ with the operating conditions of the
compressor. The program will give you a theoretical discharge
temperature of the compressor. Once this temperature is
known, you may adjust the hand expansion valve. The ideal
discharge temperature is within 5°F + or – of the theoreti­
cal discharge temperature. Adjust the valve to achieve the
theoretical discharge temperature. If you do not have access
to CoolWare™, 180°F is a good target discharge temperature
for a high stage compressor. Booster applications and com­
pressors using HFC and HCFC refrigerants may run cooler.
Depending on the gas, the compressor may run hotter at
lower capacity. Compressors with high discharge pressure
may run hotter.
The first method is used for compressors with External Oil
Cooling (Thermosyphon, Water Cooled, and Glycol Cooled).
Before the initial startup of the compressor close the hand
expansion valve completely. Open the valve back up and
count the turns that it takes to fully open the valve. After
the initial startup close the valve to achieve approximately
180° F discharge temperature or the theoretical temperature
from CoolWare. Do not fully close the valve at any time while
the compressor is running.
The second method is used for compressors with Liquid
Injection Oil Cooling. Because the discharge temperature is
controlled by the Liquid Injection Thermal Expansion Valve
you will not be able adjust for the correct oil flow by using
the discharge temperature. Before the initial startup of the
compressor close the hand expansion valve completely. Open
the valve back up and count the turns that it takes to fully
open the valve. After the initial startup close the valve ¾
way. If it took 10 turns to open the valve completely, then
turn it in 5 turns. If it took 7 turns to open, then close the
valve 5¼ turns. Do not close the valve any further than ¾
the number of turns required to fully open it.
WARNING
Failure to properly adjust this valve can lead to exces-
sive noise and vibration of the compressor and package,
premature failure of the bearings, liquid loading of the
rotors, liquid starvation of the rotors and catastrophic
failure of the compressor.
2. For proper and safe operation, the compressor must be
run at the proper speed and discharge pressure. Exceeding
design conditions creates a potential hazard.
3. Rotate and lubricate motor bearings according to manu­
facturer’s recommendations PRIOR to initial start­up as
required.
4. After running the unit for approximately three hours, ad­
just liquid injection oil cooling if applicable. If unit has water
cooled oil cooling, adjust water control valve to cooler.
5. After six hours of operation, shut down and clean all
strainer elements.
6. The compressor slide valve and slide stop linear transmit­
ters should be calibrated.
7. Perform vibration analysis if equipment is available.
8. Refer to project IOM manual for additional documents
including custom operation and maintenance instructions.
NORMAL START-UP PROCEDURE
1. Confirm system conditions permit starting the compres sor.
2. Press the [RUN] key.
3. Allow the compressor to start­up and stabilize. Press the
[AUTO] key immediately below the V ratio label on the oper­
ating display screen. Press the [AUTO] key im mediately below
the SV POS label on the operating display. The compres sor
is now operating in the automa tic mode.
4. Observe the compressor unit for mechanical tightness of
the external piping, bolts and valves. Ensure that the ma­
chine is clean from oil and refrigerant leaks. If any of these
occur, shut down the compressor and correct the problem
as necessary using good safety precautions.
5. RETIGHTEN MANWAY BOLTS at condenser design
pressure (while system is running) to 180 ft-lb.
RESTARTING COMPRESSOR UNIT AFTER CONTROL
POWER INTERRUPTION (PLANT POWER FAILURE)
1. Check variable setpoints.
2. Follow normal start­up procedure.
VFD SKIP FREQUENCIES
Criteria for Identifying Elevated Energy on VFD
Packages and Establishing “Skip” Frequencies
With the RWH running loaded at full speed, the entire package
must be physically checked for elevated energy, including any
corresponding extremities such as valves, liquid injection piping,
brackets, tubing, oil cooler and oil piping. The VFD speed is to
be decreased by 100 rpm increments and the entire package
physically checked for elevated energy at each stage until the
minimum speed range is reached. As the high energy hot spots
are identified, they are to be checked with a vibration meter
and any readings that meet or exceed one inch per second
must have that frequency range skipped in the microprocessor
for the VFD, eliminating the ability of the package to operate
within that frequency range. Each identified range needs to have
the skip set to as narrow a frequency band as possible, only
making it wider until full range is accommodated. Please also
reference 070.902­IB for acceptable package vibration readings.
Skip frequencies should be reviewed and verified annually.